Gilman is a city located in Iroquois County, Illinois. As of the 2000 census, the city had a total population of 1,793.
Gilman is located at 40°46'3" North, 87°59'37" West (40.767466, -87.993611)1.
According to the United States Census Bureau, the city has a total area of 5.5 km2 (2.1 mi2). 5.5 km2 (2.1 mi2) of it is land and 0.1 km2 (0.04 mi2) of it is water. The total area is 0.94% water.